Effectiveness of cough exercise and expiratory muscle training: A meta-analysis

Abstract

Coughing is a defensive reflex action of the airway that removes foreign objects and mucus. Here, meta-analysis was performed to review the results of previous studies regarding the effects of coughing exercise and expiratory muscle training (EMT), and to examine the effectiveness of EMT in enhancing cough functions. A systematic literature search was performed using the EBMR, CINAHL, PEDro, MEDLINE, and Ichushi Web (NPO Japan Medical Abstracts Society) databases. Based on a methodological framework, a critical review was performed and summary effect sizes were calculated by applying the random effects model. Both the forced expiration technique (FET) and coughing alone significantly increased mucus clearance. EMT significantly increased expiratory muscle strength, suggesting that it is possible to improve cough effectiveness by EMT. Further studies with larger and more diverse sample groups are necessary to determine the effects of enhancing expiratory muscle strength on cough effectiveness. Copyright © 2006 by the Society of Physical Therapy Science.